Traditional engine fuel control systems use a mechanical linkage to connect the accelerator pedal to the throttle valve. Engine idle speed is then controlled by a mechanical system that manipulates the pedal position according to engine load.
Since the mid-1970's electronic throttle control or “drive-by-wire” systems have been developed. Electronic throttle control systems replace the mechanical linkage between the accelerator pedal and the throttle valve with an electronic linkage. These types of systems have become increasingly common on modern automobiles.
Generally, at least one sensor is typically placed at the base of the accelerator pedal and its position is communicated to the engine controller. At the engine, a throttle position sensor and an electronically controlled motor then regulate the throttle to maintain a precise engine speed through a feedback system between the throttle position sensor and the electronically controlled motor. An example of an electronic throttle control system can be found with reference to U.S. Pat. No. 6,289,874 to Keefover, the entire specification of which is incorporated herein by reference.
In conventional electronic throttle control systems, the various components of the throttle position sensor stator and connector assembly are mounted to the casting of the throttle body. The connector assembly is also connected to the motor. The throttle position sensor is placed in close proximity with the rotating shaft of the throttle valve. The throttle position sensor used to provide data so that the angular position of the throttle valve can be determined. Typical conventional throttle control systems use contact sensors such as potentiometers as well as non-contact sensors such as Hall Effect sensors which incorporate a magnet and stator configuration. These conventional sensors can often be bulky and difficult to align during assembly. Furthermore, angular position sensors have been incorporated with applications other than throttle control valves. For example, angular position sensors may be used in conjunction with other systems such as turbo actuators and exhaust gas recirculation valves, canister purge valves and transmission shift valves.